Bridge Over Troubled Waters EarthCache
Hidden : 1/22/2010
Difficulty:
2 out of 5
Terrain:
1.5 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:


In order to count this Earthcache as a find, you must complete the following tasks and email the answers to me.

1. Describe the appearance of the water.

2. Estimate the distance between the top of the water and the bottom of the bridge.

3. At this particular area, what would happen if it were to flood?

4. Describe the weir and explain its purpose.

This Earthcache is located along the bike trail at the inlet to Lake Kampeska. Parking can be found across the street. Enjoy!

About 20 thousand years ago, the last series of glaciers made its way across North America like a pancake spreading on a griddle. The large amounts of snow falling on the center of the glacier caused it to squeeze outward in all directions and the edges to creep farther and farther over the land.

The ice sheet eventually moved southward from the northeast and covered present-day South Dakota. As this glacier was moving into the area, a massive highland forced it to split in two. The larger slice moved in southeasterly direction, while the smaller segment was pushed south and west through what is now the James River Valley. Slowly, the larger piece of the glacier climbed up the dividing highland and joined up with the smaller segment in a continuous frozen expanse that buried the land.

Geologists believe that the glacier piled up as much as 1600 feet of ice in the area. Because of the massive thickness of this ice sheet and its weight, the glacier acted like a bulldozer and left quite a mark on the land it traveled across. It scoured and scraped the land, leveled high places and filled in low areas, smoothed some surfaces and gouged others. The landscape was further altered by the sudden moving, stopping, retreating, and moving again. When the glacier moved, it marked the ground with rocks and gravel frozen in its base. Sharp-edged rocks cut long grooves in bedrock and fine silt and clay polished surfaces smooth in places like Beadle, Grant, and Marshall counties. When the glacier stalled or retreated, it left behind piles of sediments called moraines. A moraine is an accumulation of unconsolidated glacial debris, such as soil and rock. All of the hills, ridges, and knolls found in the area are examples of these moraines. The smaller moraines show where the glacier was simply stalled, while the larger moraines indicate where the glacier retreated.

The Coteau des Prairies highland is the largest example of a glacial moraine in the area. This enormous wedge-shaped plateau, with its point just over the North Dakota line and its base in northwestern Iowa, grew from the ancient highland that divided the glacier. When the eastern slice of the glacier climbed up the highland, it brought with it eroded rock debris that were embedded in the bottom of the glacier. The more the glacier advanced, the more ice and frozen sediment it piled onto the highland. For as long as the glacier crept forward, the highland, with its growing pile of glacial debris, acted like a wall being built layer upon layer. When the glacier finally retreated in its entirety (when the ice finally melted), all of the sediments that were once frozen into the glacier were left behind.

Glacial lakes were also created as the glacier retreated. As the glacier started to melt away, huge chunks of ice broke away from the main ice sheet and were left behind. As the ice chunks melted, the land around them slumped in and created large round holes that later filled with water. Some of these holes were filled in by glacial streams, which were formed by the steady trickle of melting ice. Other holes were filled when the melting glacier sent forth a massive flood, which in turn created the ancient Glacial Lake Agassiz. With the exception of Lake Agassiz, which no longer exists today, these are the glacial lakes that now dot the landscape. Over 120 of these glacial lakes (about two-thirds of the state’s total) can be found in northeastern South Dakota - Lake Kampeska included. It is these lakes that give the region its name.

Flooding is one of the major problems Lake Kampeska faces today. Like most glacial lakes in the area, Lake Kampeska is spring fed, but it also takes in water from the Big Sioux River. David Jensen, in his article “Legendary Lake Kampeska,” explains this process: “When the spring runoff fills the Big Sioux, excess water enters Kampeska and the lake swells, sometimes flooding.”

Three disastrous floods have occurred in Watertown since 1993, and each time, at least 100 families were forced to evacuate their homes. May of 1993 brought on the area’s worst flood since 1969. The oncoming of a late spring melted the large amounts of snow and caused Lake Kampeska to rise thirty-six inches above full capacity (Craig 1A). This 100-year flood caused many citizens living at Lake Kampeska to evacuate. After clean-up had started, city officials looked for a solution to prevent future flooding. The city of Watertown proposed building a dam ten miles upstream from Watertown on the Mahoney Creek site of the Big Sioux River. The earthen Mahoney Creek Dam would be able to hold up to 44,000 acre-feet of water. It would restrain and slowly release floodwaters into the Big Sioux River, but the retention area would dry up during periods of normal precipitation. This project would also entail constructing a 600-foot-wide emergency spillway and possibly relocating roads and utilities. Additionally, over 6000 acres of farmland would have to be purchased and the habitats of fish and wildlife that would be destroyed in the process of constructing the dam would need to be restored (Hammond 1A). This proposal was taken to the county to vote on, but was defeated. After the proposal was rejected, no other solutions for flood prevention were offered.

In 1997, heavy rains and large amounts of snowfall brought a record-breaking, history-making flood to the city of Watertown. On April 2, 1997, the Big Sioux River was already two and a half inches above full, but the rains were far from being over. It was pumping 5000 cubic feet of water per second into Lake Kampeska; a half inch of rain changed the flow to 9000 cubic feet of water per second. Lake Kampeska was quickly rising. (Mooney, “City Council Sees”). From April 2, 1997, to April 6, 1997, a period of four days, Lake Kampeska had risen seventy-six and a half inches, making the lake seventy-four and a half inches above full. The recent heavy rains and amount of snow melting, along with a blizzard that struck during the night of April 5, nearly doubled Kampeska’s previous record of forty-six and a half-inches above full set in 1969. Dubbed a 500-year flood, this flood damaged 300 homes and caused an estimated $130 million in damages (Dailey 1A). Because of flooding, 5000 people, a fourth of Watertown, were evacuated; some had relatives in town unaffected by the flood, but many were placed in one of four evacuation centers throughout town. The entire city, except for emergency centers, was literally shut down on April 7, 1997; travel was not allowed and businesses were closed (Dailey 1A). Throughout the next few days, travel was restricted to only a few streets. Businesses along those streets were allowed to reopen, but other businesses and schools remained closed for a week.

Just as water had flooded the town, volunteers also flooded the town in an effort to help. High school students, the South Dakota National Guard, and about two hundred inmates from the state prison helped fill sandbags; churches opened their doors to displaced families and provided meals and shelter; the Salvation Army, along with two community service groups from the high school, collected essential items and distributed them to the evacuees. After President Clinton signed a statewide disaster declaration for South Dakota, the Federal Emergency Management Agency, FEMA, moved into to Watertown (Gale 1A). Slowly, as the clean-up process and repairs began, people were allowed back into their homes; however, those evacuated from Lake Kampeska were not permitted to return to their homes until early May, a good five weeks after the flood had occurred.

While clean up continued, specialists from FEMA and members from the Department of Environmental and Natural Resources studied the situation in order to provide the city of Watertown with a solution. Once again, the issue of building a dam over Mahoney Creek to stop water from flowing into the Big Sioux River was brought to light. The city of Watertown was offered $15 million from the federal government for the dam project. Another $5 million would be used from FEMA funds (Specht 1A). Once again, the county voted on the issue, and once again, the proposal was defeated. Unlike the flood prevention efforts of 1993 though, the city did not stop at the defeat of Mahoney Creek Dam. Instead, levees were built along the Big Sioux River in preparation for another flood.

The city of Watertown saw yet another 100-year flood in 2001. Lake Kampeska rose from 20 inches below full on April 6, 2001 to 45 inches above full on April 10, 2001. Two days later, the lake hit sixty-six inches above full?six inches below the 1997 record (Nielsen). Early on, the water had already chased dozens of lakeside families out of their homes. Volunteers once more returned to the flood scene to offer their help. 150 inmates from the state prison worked to reinforce a levee that protects about a thirty-square-block area of Watertown; high school students and other volunteers quickly filled sandbags on the lake’s south shore (Neilsen).

Once again, in response to the flood, the city of Watertown suggested that the city move forward with the Mahoney Creek Dam initiative. This time, however, the vote was restricted to the residents of Watertown; farmers whose land would have to be taken to build the dam were not allowed to vote because they do not reside within city limits. On the third try at the voting booth, voters decided 3,314 to 2,519 to support construction of a dam on the Mahoney Creek (Mooney, “Watertown Approves Dam” 1A). After the approval of the project, the city of Watertown worked to create a design for the dam and find money to build it. However, in January of 2002, after several debates between farmers and city officials over the Mahoney Creek Dam project, the city decided to halt progress on the project and look at other solutions (O’Keefe 1A). The Lake Pelican Water Project District suggested building several small dams along the Big Sioux River instead of one large dam. This plan, supporters argue, would prevent flooding and it would allow farmers to keep most of their farmland. The city of Watertown has not accepted this proposal and is still investigating other possible prevention methods.

Pollution is another issue that Lake Kampeska faces--an issue that has been exacerbated by flooding.. In his article “Legendary Lake Kampeska,” David Jensen explains that Kampeska is a silt lake, meaning its river inlet is also its outlet. “Water from the river stops flowing and drops its silt. Upriver runoff adds pollutants.” Every time there is a flood, pollutants from farmlands, roads, and residential lawns are carried into the lake. Lake Kampeska did not always have this silt problem. Jensen’s article mentions that the Lake’s natural outlet was filled in prior to World War II in order to make space for the lengthened airport runway. Filling the Kampeska’s natural outlet exacerbated the silt problem. Jensen explains that much has already been done to fight the pollution and algae in Lake Kampeska, “including the construction of a weir (fence-like dam) at the inlet.”

Pictures of the 1997 Flood: (visit link)

Resources:

Craig, John. “Waters on the Rise.” Watertown Public Opinion 20 May 1993: 1A. Print.

Dailey, Milo. “Flood Wins Battle; City Wins War.” Watertown Public Opinion 7 April 1997: 1A. Print.

Gale, Dennis. “Disaster Declaration Issued.” Watertown Public Opinion 8 April 1997: 1A. Print.

Hammond, Wayne. “Mahoney Creek Proposed Again.” Watertown Public Opinion 1 June 1993: 1A. Print.

Jensen, David. "Legendary Lake Kampeska." South Dakota Magazine, January/February 2007: 20-27. Print. 

Mooney, Bob. “City Council Sees ‘if’ Become a Flooding Reality.” Watertown Public Opinion 2 April 1997: 1A. Print.

---. “Watertown Approves Dam.” Watertown Public Opinion 1 August 2001: 1A. Print.

Nielsen, Jennifer. “Watertown Scrambles to Limit Flood Damage.” Watertown Public Opinion 8 April 2001: 1A. Print.

O’Keefe, Terry. “Mahoney Creek Halted.” Watertown Public Opinion 23 January 2002: 1A. Print.

Specht, Wayne. “Mayor: Time to Consider a New Look at Watersheds.” Watertown Public Opinion 15 April 1997: 1A. Print.

NOT A LOGGING REQUIREMENT: Feel free to post pictures of your group at the area or the area itself - I love looking at the pictures.

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